A rotor and stator that have chambers that are in communication with one another but which must be sealed from the outside environment, require a rotating bearing and seal that enables rotation of the rotor while sealing it against the stator. One application for such a seal is in accelerator beam experiments wherein a particle beam generated in a stationary housing is to strike a rapidly rotating target, and with the beam and target being maintained in a high vacuum. U.S. Pat. No. 4,118,042 by Rex Booth entitled Air Bearing Vacuum Seal Assembly, describes an arrangement whereby the rotor can be rotated at high speed while minimizing the entrance of air into the communicating vacuum chambers of the rotor and stator. The patent describes an arrangement wherein the rotor is supported on the stator solely by air bearings. The air bearings maintain a very small space between bearing faces on the rotor and stator to minimize the flow of air through the space into the vaccum chambers. Furthermore, the patent describes the use of air outlets in the bearing faces to draw away pressure air that slightly separates the faces and that might otherwise leak into the vaccum chambers. While such an arrangement can enable precision rotation of the rotor at high speeds while reducing air leakage into the vacuum chambers to a low level, it has disadvantages. One disadvantage is that air bearings of moderate size cannot easily support large loads, as where the rotor has considerable overhanging weight. In addition, a conical air bearing portion that provides radial thrust, adds substantially to the cost of the assembly.